Optimal design of a low-power, phase-switching modulator for implantable medical applications.

Since first proposed in JSSC [1], phase-switching modulation has been proved to be a viable transmission scheme. In this paper, we explored the maximum data-rate of phase-switching modulation and proposed a modified quadrature oscillator with a self-bias circuit to isolate the disturbance in power supply and ground. Dividers and filter are also optimized to minimize parasitic resistor and capacitor. The prototype is fabricated in a 0.18 μm CMOS process, with an active chip area of about 0.13 mm × 0.35 mm. The total power consumption of the modulator is only 2 mW with an energy efficiency of 80 pJ/Bit. This modulator has been successfully embedded in a direct-up conversion transmitter for medical application. • We present the system design of a phase-switching modulator with maximized data rate. • We proposed a modified quadrature oscillator with a self-bias circuit to isolate the disturbance in power supply and ground. • We investigated the designs for divider and filter to explore its design space and achieve optimal performance. [ABSTRACT FROM AUTHOR]